In a world where everybody implements MVC web framework in their favorite language, reimplements window managers in their favorite language, and reimplements all manner of other software simply because it wasn't in their favorite language... there's a reason all the communities just bind to GTK, QT, and wxWidgets and don't reimplement widget frameworks from scratch in their favorite language, even for languages much better funded and bigger than all the functional programming communities put together. Just the bindings can be major and in some cases unsustainable efforts for smaller communities.
A minimal toolkit that can do interesting things is a few weeks of work in Haskell. Here's an implementation of one: https://github.com/Peaker/bottle/tree/master/bottlelib/Graph...
It is incomplete and non-comprehensive, but adding the nuances needed to make it more complete and comprehensive wouldn't be too much work (it's simply not our focus in the project).
So it's minimal AND incomplete. Not even minimal and complete. That's what the parent was saying. And it will likely stay that way (as it's not even your focus in the project), and be forgotten.
There are tons of toolkits like that.
(On the other hand, I do also think that one of the problems FRP faces is in trying to bind to a very not-functional world. UI toolkits in particular are deeply, fundamentally imperative, and such massive endeavors that the idea of replacing one with a functional equivalent is laughable, because the resources aren't there, even though there aren't any fundamental blockers. Needing to hook up your FRP to such toolkits to get them to do anything is a huge up-front penalty to pay to even get one started.)